So far, this board has been very helpful in providing information about my Victory, and recently, my newly-purchased, and anxiously awaited, 2nd Model HE in .455.

As a result, I thought I'd see if I could get a bit of info on my only other S&W revolver. I bought this .38 Special 22 years ago, as pictured, with the rubber grips on it. Based on other posts and pictures here I am going with this being a K-38 Masterpiece (but seek confirmation).

S/N is K99387, so any guidance on year of manufacturer would be appreciated. As well, I'd like to get a suitable pair of S&W wood grips for it, so details or pictures of the appropriate grips would also be appreciated. Were the grips numbered to the firearm?

Yes, a K-38 Masterpiece and yes, 1950. I have K100091, which shipped in December of that year, and K78197, from the preceding February. If you can find walnut diamond magnas from the late '40s through the mid-'50s, they will be appropriate for your gun. Also, in the early 1950s S&W was beginning to offer optional target stocks. A set of nice early targets (which were not numbered to the gun) would also look good on your K-38.